Skip to content
Snippets Groups Projects
  1. May 24, 2022
    • Masahiro Yamada's avatar
      genksyms: adjust the output format to modpost · 5ce2176b
      Masahiro Yamada authored
      
      Make genksyms output symbol versions in the format modpost expects,
      so the 'sed' is unneeded.
      
      This commit makes *.symversions completely unneeded.
      
      I will keep *.symversions in .gitignore and 'make clean' for a while.
      Otherwise, 'git status' might be surprising.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Reviewed-by: default avatarNicolas Schier <nicolas@fjasle.eu>
      Tested-by: default avatarNathan Chancellor <nathan@kernel.org>
      Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
      5ce2176b
    • Masahiro Yamada's avatar
      kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS · 7b453719
      Masahiro Yamada authored
      
      include/{linux,asm-generic}/export.h defines a weak symbol, __crc_*
      as a placeholder.
      
      Genksyms writes the version CRCs into the linker script, which will be
      used for filling the __crc_* symbols. The linker script format depends
      on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset
      to the reference of CRC.
      
      It is time to get rid of this complexity.
      
      Now that modpost parses text files (.*.cmd) to collect all the CRCs,
      it can generate C code that will be linked to the vmlinux or modules.
      
      Generate a new C file, .vmlinux.export.c, which contains the CRCs of
      symbols exported by vmlinux. It is compiled and linked to vmlinux in
      scripts/link-vmlinux.sh.
      
      Put the CRCs of symbols exported by modules into the existing *.mod.c
      files. No additional build step is needed for modules. As before,
      *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal.
      
      No linker magic is used here. The new C implementation works in the
      same way, whether CONFIG_RELOCATABLE is enabled or not.
      CONFIG_MODULE_REL_CRCS is no longer needed.
      
      Previously, Kbuild invoked additional $(LD) to update the CRCs in
      objects, but this step is unneeded too.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Tested-by: default avatarNathan Chancellor <nathan@kernel.org>
      Tested-by: default avatarNicolas Schier <nicolas@fjasle.eu>
      Reviewed-by: default avatarNicolas Schier <nicolas@fjasle.eu>
      Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
      7b453719
  2. May 01, 2021
  3. Feb 16, 2021
  4. Dec 21, 2020
    • Marco Elver's avatar
      genksyms: Ignore module scoped _Static_assert() · 9ab55d7f
      Marco Elver authored
      
      The C11 _Static_assert() keyword may be used at module scope, and we
      need to teach genksyms about it to not abort with an error. We currently
      have a growing number of static_assert() (but also direct usage of
      _Static_assert()) users at module scope:
      
      	git grep -E '^_Static_assert\(|^static_assert\(' | grep -v '^tools' | wc -l
      	135
      
      More recently, when enabling CONFIG_MODVERSIONS with CONFIG_KCSAN, we
      observe a number of warnings:
      
      	WARNING: modpost: EXPORT symbol "<..all kcsan symbols..>" [vmlinux] [...]
      
      When running a preprocessed source through 'genksyms -w' a number of
      syntax errors point at usage of static_assert()s. In the case of
      kernel/kcsan/encoding.h, new static_assert()s had been introduced which
      used expressions that appear to cause genksyms to not even be able to
      recover from the syntax error gracefully (as it appears was the case
      previously).
      
      Therefore, make genksyms ignore all _Static_assert() and the contained
      expression. With the fix, usage of _Static_assert() no longer cause
      "syntax error" all over the kernel, and the above modpost warnings for
      KCSAN are gone, too.
      
      Signed-off-by: default avatarMarco Elver <elver@google.com>
      Acked-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      9ab55d7f
  5. Aug 18, 2020
  6. Aug 09, 2020
    • Masahiro Yamada's avatar
      kbuild: introduce hostprogs-always-y and userprogs-always-y · faabed29
      Masahiro Yamada authored
      
      To build host programs, you need to add the program names to 'hostprogs'
      to use the necessary build rule, but it is not enough to build them
      because there is no dependency.
      
      There are two types of host programs: built as the prerequisite of
      another (e.g. gen_crc32table in lib/Makefile), or always built when
      Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile).
      
      The latter is typical in Makefiles under scripts/, which contains host
      programs globally used during the kernel build. To build them, you need
      to add them to both 'hostprogs' and 'always-y'.
      
      This commit adds hostprogs-always-y as a shorthand.
      
      The same applies to user programs. net/bpfilter/Makefile builds
      bpfilter_umh on demand, hence always-y is unneeded. In contrast,
      programs under samples/ are added to both 'userprogs' and 'always-y'
      so they are always built when Kbuild visits the Makefiles.
      
      userprogs-always-y works as a shorthand.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Acked-by: default avatarMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
      faabed29
  7. Mar 25, 2020
  8. Feb 03, 2020
    • Masahiro Yamada's avatar
      kbuild: rename hostprogs-y/always to hostprogs/always-y · 5f2fb52f
      Masahiro Yamada authored
      
      In old days, the "host-progs" syntax was used for specifying host
      programs. It was renamed to the current "hostprogs-y" in 2004.
      
      It is typically useful in scripts/Makefile because it allows Kbuild to
      selectively compile host programs based on the kernel configuration.
      
      This commit renames like follows:
      
        always       ->  always-y
        hostprogs-y  ->  hostprogs
      
      So, scripts/Makefile will look like this:
      
        always-$(CONFIG_BUILD_BIN2C) += ...
        always-$(CONFIG_KALLSYMS)    += ...
            ...
        hostprogs := $(always-y) $(always-m)
      
      I think this makes more sense because a host program is always a host
      program, irrespective of the kernel configuration. We want to specify
      which ones to compile by CONFIG options, so always-y will be handier.
      
      The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
      compatibility for a while.
      
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      5f2fb52f
  9. Sep 14, 2019
    • Masahiro Yamada's avatar
      genksyms: convert to SPDX License Identifier for lex.l and parse.y · 77564a48
      Masahiro Yamada authored
      
      I used the C comment style (/* ... */) for the flex and bison files
      as in Kconfig (scripts/kconfig/{lexer.l,parser.y})
      
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      77564a48
    • Masahiro Yamada's avatar
      export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols · 69a94abb
      Masahiro Yamada authored
      
      Arnd Bergmann reported false-positive modpost warnings detected by his
      randconfig testing of linux-next.
      
      Actually, this happens under the combination of CONFIG_MODVERSIONS
      and CONFIG_TRIM_UNUSED_KSYMS since commit 15bfc234 ("modpost:
      check for static EXPORT_SYMBOL* functions").
      
      For example, arch/arm/config/multi_v7_defconfig + CONFIG_MODVERSIONS
      + CONFIG_TRIM_UNUSED_KSYMS produces the following false-positives:
      
      WARNING: "__lshrdi3" [vmlinux] is a static (unknown)
      WARNING: "__ashrdi3" [vmlinux] is a static (unknown)
      WARNING: "__aeabi_lasr" [vmlinux] is a static (unknown)
      WARNING: "__aeabi_llsr" [vmlinux] is a static (unknown)
      WARNING: "ftrace_set_clr_event" [vmlinux] is a static (unknown)
      WARNING: "__muldi3" [vmlinux] is a static (unknown)
      WARNING: "__aeabi_ulcmp" [vmlinux] is a static (unknown)
      WARNING: "__ucmpdi2" [vmlinux] is a static (unknown)
      WARNING: "__aeabi_lmul" [vmlinux] is a static (unknown)
      WARNING: "__bswapsi2" [vmlinux] is a static (unknown)
      WARNING: "__bswapdi2" [vmlinux] is a static (unknown)
      WARNING: "__ashldi3" [vmlinux] is a static (unknown)
      WARNING: "__aeabi_llsl" [vmlinux] is a static (unknown)
      
      The root cause of the problem is not in the modpost, but in the
      implementation of CONFIG_TRIM_UNUSED_KSYMS.
      
      If there is at least one untrimmed symbol in the file, genksyms is
      invoked to calculate CRC of *all* the exported symbols in that file
      even if some of them have been trimmed due to no caller existing.
      
      As a result, .tmp_*.ver files contain CRC of trimmed symbols, thus
      unneeded, orphan __crc* symbols are added to objects. It had been
      harmless until recently.
      
      With commit 15bfc234 ("modpost: check for static EXPORT_SYMBOL*
      functions"), it is now harmful because the bogus __crc* symbols make
      modpost call sym_update_crc() to add the symbols to the hash table,
      but there is no one that clears the ->is_static member.
      
      I gave Fixes to the first commit that uncovered the issue, but the
      potential problem has long existed since commit f2355416
      ("export.h: allow for per-symbol configurable EXPORT_SYMBOL()").
      
      Fixes: 15bfc234 ("modpost: check for static EXPORT_SYMBOL* functions")
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Tested-by: default avatarArnd Bergmann <arnd@arndb.de>
      69a94abb
  10. Sep 06, 2019
  11. Aug 13, 2019
    • Masahiro Yamada's avatar
      kbuild: make bison create C file and header in a single pattern rule · 6ba7dc66
      Masahiro Yamada authored
      We generally expect bison to create not only a C file, but also a
      header, which will be included from the lexer.
      
      Currently, Kbuild generates them in separate rules. So, for instance,
      when building Kconfig, you will notice bison is invoked twice:
      
        HOSTCC  scripts/kconfig/conf.o
        HOSTCC  scripts/kconfig/confdata.o
        HOSTCC  scripts/kconfig/expr.o
        LEX     scripts/kconfig/lexer.lex.c
        YACC    scripts/kconfig/parser.tab.h
        HOSTCC  scripts/kconfig/lexer.lex.o
        YACC    scripts/kconfig/parser.tab.c
        HOSTCC  scripts/kconfig/parser.tab.o
        HOSTCC  scripts/kconfig/preprocess.o
        HOSTCC  scripts/kconfig/symbol.o
        HOSTLD  scripts/kconfig/conf
      
      Make handles such cases nicely in pattern rules [1]. Merge the two
      rules so that one invokcation of bison can generate both of them.
      
        HOSTCC  scripts/kconfig/conf.o
        HOSTCC  scripts/kconfig/confdata.o
        HOSTCC  scripts/kconfig/expr.o
        LEX     scripts/kconfig/lexer.lex.c
        YACC    scripts/kconfig/parser.tab.[ch]
        HOSTCC  scripts/kconfig/lexer.lex.o
        HOSTCC  scripts/kconfig/parser.tab.o
        HOSTCC  scripts/kconfig/preprocess.o
        HOSTCC  scripts/kconfig/symbol.o
        HOSTLD  scripts/kconfig/conf
      
      [1] Pattern rule
      
      GNU Make manual says:
      "Pattern rules may have more than one target. Unlike normal rules,
      this does not act as many different rules with the same prerequisites
      and recipe. If a pattern rule has multiple targets, make knows that
      the rule's recipe is responsible for making all of the targets. The
      recipe is executed only once to make all the targets. When searching
      for a pattern rule to match a target, the target patterns of a rule
      other than the one that matches the target in need of a rule are
      incidental: make worries only about giving a recipe and prerequisites
      to the file presently in question. However, when this file's recipe is
      run, the other targets are marked as having been updated themselves."
      
      https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html
      
      
      
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      6ba7dc66
  12. Jun 23, 2019
    • Will Deacon's avatar
      genksyms: Teach parser about 128-bit built-in types · a222061b
      Will Deacon authored
      
      __uint128_t crops up in a few files that export symbols to modules, so
      teach genksyms about it and the other GCC built-in 128-bit integer types
      so that we don't end up skipping the CRC generation for some symbols due
      to the parser failing to spot them:
      
        | WARNING: EXPORT symbol "kernel_neon_begin" [vmlinux] version
        |          generation failed, symbol will not be versioned.
        | ld: arch/arm64/kernel/fpsimd.o: relocation R_AARCH64_ABS32 against
        |     `__crc_kernel_neon_begin' can not be used when making a shared
        |     object
        | ld: arch/arm64/kernel/fpsimd.o:(.data+0x0): dangerous relocation:
        |     unsupported relocation
      
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      a222061b
  13. May 30, 2019
  14. May 21, 2019
  15. May 18, 2019
  16. May 17, 2018
  17. May 05, 2018
  18. Apr 07, 2018
  19. Jan 13, 2018
  20. Nov 02, 2017
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  21. Sep 08, 2017
    • Linus Torvalds's avatar
      genksyms: fix gperf removal conversion · 3aea311c
      Linus Torvalds authored
      
      I had stupidly missed one special use of 'is_reserved_word()' when I
      converted the code to avoid gperf.
      
      I had changed that function to return the token ID directly rather than
      a pointer to the token descriptor structure, but that meant that the
      test for "is this a reserved word" changed from checking the return
      value against NULL, to checking that it wasn't negative.
      
      And while I had converted the main token parser over, I missed the
      special case of the typeof phrase handling.  And since our dependency
      chain for genksyms does not include the genksyms program itself
      changing, my kernel rebuild didn't show the problem.
      
      Fixes: bb3290d9 ("Remove gperf usage from toolchain")
      Reported-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3aea311c
  22. Aug 19, 2017
  23. Jun 05, 2017
  24. Feb 03, 2017
    • Ard Biesheuvel's avatar
      kbuild: modversions: add infrastructure for emitting relative CRCs · 56067812
      Ard Biesheuvel authored
      
      This add the kbuild infrastructure that will allow architectures to emit
      vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
      where the actual value is stored. This works around problems with CRCs
      being mistaken for relocatable symbols on kernels that self relocate at
      runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)
      
      For the kbuild side of things, this comes down to the following:
      
       - introducing a Kconfig symbol MODULE_REL_CRCS
      
       - adding a -R switch to genksyms to instruct it to emit the CRC symbols
         as references into the .rodata section
      
       - making modpost distinguish such references from absolute CRC symbols
         by the section index (SHN_ABS)
      
       - making kallsyms disregard non-absolute symbols with a __crc_ prefix
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      56067812
  25. Jan 05, 2017
  26. Nov 29, 2016
  27. Aug 25, 2016
  28. Apr 20, 2016
  29. Dec 09, 2015
    • Michal Marek's avatar
      genksyms: Handle string literals with spaces in reference files · a78f70e8
      Michal Marek authored
      
      The reference files use spaces to separate tokens, however, we must
      preserve spaces inside string literals. Currently the only case in the
      tree is struct edac_raw_error_desc in <linux/edac.h>:
      
      $ KBUILD_SYMTYPES=1 make -s drivers/edac/amd64_edac.symtypes
      $ mv drivers/edac/amd64_edac.{symtypes,symref}
      $ KBUILD_SYMTYPES=1 make -s drivers/edac/amd64_edac.symtypes
      drivers/edac/amd64_edac.c:527: warning: amd64_get_dram_hole_info: modversion changed because of changes in struct edac_raw_error_desc
      
      Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
      a78f70e8
Loading